In collaboration with investigators at the Tripler Army Medical Center, Hawaii, we developed a proposal to examine the effects of epidural analgesia on the course of labor and cesarean delivery rate in nullipara. We selected two periods: from October 1992 to September 1993 when epidural analgesia was not available, and from October 1995 to Spetember 1996 when epidural analgesia was used in 65% of births. Detailed information on maternal demographic characteristics, course of labor and delivery, and labor analgesia were extracted from the medical records (about 600 patients in each period). We have completed data collection. In the data analysis, we compared the duration of labor and rates of cesarean delivery between these two periods. In addition, we examined whether epidural analgesia increases the incidence of occiput posterior position and maternal hyperthermia. We will finish the data analysis by the end of 2000.